Can't get MIDI to work reliably

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kevinz
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Can't get MIDI to work reliably

Post by kevinz »

Hello, all, very newbie here. I'm taking a music course in Music Technology, but plan to complete all of the assignments using my Linux system instead of the Windows and web-based systems specified in the course. Our first assignment is to create 'patches' for a web-based 'analogue' synthesizer at soundation.com.

I'm first trying to just get my system to work reliably. I'm using Ubuntu 18.04 with QjackCtl 0.4.5, Qsynth 0.5.0, FluidSynth 1.1.9, and VMPK 0.4.0. I've connected a Korg MicroKey MIDI keybaord to my system. This system works sometimes, especially on a freshly-booted system. Most other times, however, it refuses to output a sound.

Right now, the state of my system is this: Before running qjackCtl or Qsynth, I can hear output using the Sound control panel, from Line Out, using the Test Speaker buttons. If I run QjackCtl, with no connections shown in the Connect window, (but some created automaticallly in the Patchbay window), I can still hear output, using the Sound control panel, from Line Out, using the Test Speaker buttons. As soon as I run Qsynth, I can no longer hear the Test Speaker buttons. In fact, they no longer change from "Test->Stop->Test" and just display Test. I also can't hear any keyboard sounds.

If I quit from Qsynth, I can again hear the Test Speaker buttons, although the first time i press it, the voice sounds very scratchy, but not anytime after the first time.

Can anyone suggest what I can try next, to get my system to work every time I try to set it up? Let me know if there's anything else I can tell you about my system or my actions that would help you help me.

Thanks so much for your advice and guidance.

-Kevin
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bluebell
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Re: Can't get MIDI to work reliably

Post by bluebell »

"Test speaker" looks like audio, not like MIDI.

You probably don't know that there are multiple audio systems in Linux and only one can own the audio interface. Many music software uses jack. Qjackctl is a tool to start, stop and configure jack.

Many other software uses Pulseaudio. But jack and Pulseaudio cannot own the audio interface at the same time.

One solution is using jack_sink in Pulseaudio, so it outputs via jack. Jack must me up and running for this mode of operation.

https://github.com/jackaudio/jackaudio. ... ulseOnJack

Linux – MOTU UltraLite AVB – Qtractor – http://suedwestlicht.saar.de/

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